• International Journal of Oral Biology
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• 제42권4호
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• pp.197-201
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• 2017

A novel method for the detection of hydrogen peroxide in aqueous solution was developed via reaction between $H_2O_2$, trivalent titanium ion ($Ti^{3+}$) and 4-(2-thiazolylazo) resorcinol (TAR), resulting in a ternary complex with a maximum UV absorbance at 530 nm. The CE detection of $H_2O_2$ was fast, sensitive and cost-effective without pretreatment procedures. $H_2O_2$ was detected within 15 min at 1 to $100{\mu}M$ range with the lowest detection limit at $1.0{\mu}M$. Under the optimized CE conditions, the concentration of $H_2O_2$ in coffee or tea extract was quantitatively determined. Our results show that CE detection of the ternary complex of $H_2O_2-Ti^{3+}$-TAR has potential applications for the detection of $H_2O_2$ in aqueous sources.

• 한국분말재료학회지
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• 제11권3호
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• pp.193-201
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• 2004

1960년 Au-Si계 합금에서 처음으로 비정질상이 급속 응고법에 의해 보고된 이래/sup 1)/ 지난 40년 간 많은 합금계에서 비정질상이 보고되어졌다. 대표적으로 Fe-, Ni-, Co기 합금 등 많은 합금계에서 비정질상이 보고되었으나, 비정질상의 형성을 위해서는 약 105 K/s이상의 높은 냉각속도를 필요로 하였다. 1980년대 수백 K/s의 낮은 냉각속도 하에서도 비정질상이 형성될 수 있는 다원계 합금(multi-component alloy)이 Mg-Ln-(Ni, Cu, Zn), Ln-Al-TM 합금에서 보고되어 졌으나 많은 관심을 받지 못하다가 1993년 Zr-Ti-Ni-Cu-Be 합금에서 수 ㎝ 크기의 비정질합금 제조가 보고되면서 전 세계적으로 많은 관심을 받게 되었다. Zr-Ti-Ni-Cu-Be계 벌크 비정질 합금이 보고된 후 Zr-(Nb,Pd)-Al-TM, Pd-Cu-Ni-P, Fe-Co-Zr-Mo-W-B, Ti-Zr-Ni-Cu-Sn등 여러 합금계에서 벌크 비정질 합금이 보고되었다. (중략)

• 한국물환경학회지
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• 제28권2호
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• pp.197-201
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• 2012

The objective of this study was to evaluate the removal efficiency of arsenite and arsenate using composite adsorbents with various mixing ratio of recycled aluminum oxides and $TiO_2$. From batch adsorption experiments, while the removal of As(III) was almost same with 4 different composite samples in the entire pH range, the removal of As(V) was substantially increased as the weight ratio of $TiO_2$ in composite samples reduced and showed anionic adsorption characteristics. Both adsorption of As (III) and As(V) on composite samples followed pseudo-second-order adsorption equation and C-3 showed faster reaction rate for the removal of arsenic. From the adsorption isotherm experiments, Langmuir isotherm explained well and the maximum adsorption capacities of arsenic were obtained with C-1.

• Nuclear Medicine and Molecular Imaging
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• 제42권4호
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• pp.285-291
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• 2008

목적: 심근관류 SPECT에서 자동정량화 소프트웨어를 이용해 관류 및 기능에 대한 객관적이고 재현성 높은 정량 값을 얻을 수 있지만, 이러한 정량값들을 이용할 때는 분절별로 적지 않은 정상변이가 있음을 고려해야 한다. 이 연구에서는 관류에 대한 정량값에서 정상변이를 고려한 새로운 지표들을 유도하고, 이러한 지표들이 임상적 유용성을 가지는지 생존심근 평가를 통해 알아보았다. 대상 및 방법: 심근관류 SPECT에서 관류의 정상변이를 구하기 위해 55명(남:여=28:27)의 관상동맥질환 저확률군을 선정하였다. 이들에게서 $^{201}Tl$ 휴식기/$^{99m}Tc-MIBI$ 부하기 심근관류 SPECT를 실시하고, 20분절 모델을 이용하여 $^{201}Tl$ 휴식기 관류정량값에 대한 각 분절의 평균(m)과 표준편차(SD)를 구하였다. 생존심근 평가를 위해서는 관상 동맥질환을 진단 받고 관상동맥우회로이식술(CABG)을 시행한 환자 48명을 연구대상에 포함하였다. 이들은 수술전 $^{201}Tl$ 휴식기/$^{99m}Tc$-MIBI 부하기 게이트/$^{201}Tl$ 24시간 지연 SPECT을 실시하였고, 수술 3개월 후 추적 게이트 SPECT를 실시하여 생존심근을 판정하였다. 수술 전 $^{201}Tl$ 24시간 지연 SPECT에서 분절별 $Q_{delay}$ (관류정량값), ${\Delta}_{delay}$ ($Q_{delay}$ - m), $Z_{delay}$ (($Q_{delay}$ - m)/SD)가 정의되었고 이들의 생존심근에 대한 진단성적은 수신자특성곡선 상의 곡선하면적(AUC)을 통해 평가하였다. 결과: 관류정량값은 분절 사이에 상당한 변이를 보여, 남자의 경우 최저치 분절에서 $51.8{\pm}6.5$, 최고치 분절에서 $87.0{\pm}5.9$였고, 여성의 경우 최저치 분절 $58.7{\pm}8.1$, 최고치 분절 $87.3{\pm}6.0$으로 나타났다. 생존심근에 대한 진단성능 평가에서 $Q_{delay}$의 AUC는 0.633인데 반해 ${\Delta}_{delay}$와 $Z_{delay}$의 AUC는 각각 0.735와 0.716으로 나타나 $Q_{delay}$에 비해 유의하게 높은 값을 보였다(각각 p=0.001, 0.018). 가장 높은 AUC를 보인 ${\Delta}_{delay}$는, 최적분리점 -24.7에서 85%의 예민도와 53%의 특이도를 가지는 것으로 나타났다. 결론: 심근관류 SPECT의 자동 정량화 분석에서 관류정량값의 정상변이는 분절에 따라 상당한 것으로 나타났다. 이들을 고려하여 유도된 정량적 지표들은 직접적인 관류정량값에 비해 생존심근 진단에서 더 나은 진단성적을 보였다. 이 연구는 심근관류 SPECT의 정량적 분석에서 정상변이의 고려가 중요함을 시사한다.

• 한국전기전자재료학회논문지
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• 제16권3호
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• pp.195-201
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• 2003

The (Ba,Bi,Sr)TiO$_3$[BBST] thin films were fabricated on Pt/Ti/SiO$_2$ /Si substrate by RF sputtering method. The effects of Ar/O$_2$ ratio on the structural and dielectric properties of BBST thin films were investigated. Increasing the Ar/O$_2$ ratio, the intensity of BaBi$_4$Ti$_4$O$_{15}$ and Bi$_4$Ti$_3$O$_{12}$ peaks were increased but (Ba$_{0.5}$Sr$_{0.5}$)TiO$_3$ peak was decreased. In the BBST thin films deposited with condition of Ar/O$_2$(90/10) ratio, the composition ratio of the Ba, Bi and Sr atoms were 0.35, 0.25 and 0.4 respectively. The Bi and Ti atoms were diffused into the Pt layers. Increasing the Ar/O$_2$ ratio, the dielectric constant of the BBST thin films were increased but the dielectric loss of the BBST thin films were decreased. The dielectric constant and dielectric loss of the BBST deposited at 90/10 of Ar/O$_2$ ratio were 319 and 2.2%. respectively . Increasing the applied voltage, the capacitance of the BBST thin films were decreased.reased.

• Applied Science and Convergence Technology
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• 제23권5호
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• pp.201-210
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• 2014

The influence of electron irradiation and hydrogen adsorption on the electronic structure of the $SrTiO_3$ (001) surface was investigated by ultraviolet photoemission spectroscopy (UPS). Upon electron irradiation of the surface, UPS revealed an electronic state within the band gap (in-gap state: IGS) with the surface kept at $1{\times}1$. This is considered to originate from oxygen vacancies at the topmost surface formed by electron-stimulated desorption of oxygen. Electron irradiation also caused a downward shift of the valence band maximum indicating downward band-bending and formation of a conductive layer on the surface. With oxygen dosage on the electron-irradiated surface, on the other hand, the IGS intensity was decreased along with upward band-bending, which points to disappearance of the conductive layer. The results indicate that electron irradiation and oxygen dosage allow us to control the surface electronic structure between semiconducting (nearly-vacancy free: NVF) and metallic (oxygen de cient: OD) regimes by changing the density of the oxygen vacancy. When the NVF surface was exposed to atomic hydrogen, in-gap states were induced along with downward band bending. The hydrogen saturation coverage was evaluated to be $3.1{\pm}0.8{\times}10^{14}cm^{-2}$ with nuclear reaction analysis. From the IGS intensity and H coverage, we argue that H is positively charged as $H^{{\sim}0:3+}$ on the NVF surface. On the OD surface, on the other hand, the IGS intensity due to oxygen vacancies was found to decrease to half the initial value with molecular hydrogen dosage. H is expected to be negatively charged as $H^-$ on the OD surface by occupying the oxygen vacancy site.

• 대한치과교정학회지
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• 제43권4호
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• pp.201-206
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• 2013

This article describes the orthodontic treatment of a 25-year-old Korean female patient with anterior crowding, including palatally displaced lateral incisors. Her facial profile was satisfactory, but 3.5 mm of maxillary anterior crowding was observed. To correct this crowding, we decided to minimize the use of the conventional fixed orthodontic appliances and employed a less bulky and more aesthetic appliance for applying light continuous force. We determined the final positions of the maxillary teeth via a working model for diagnostic set up and achieved space gaining and alignment with simple Ni-Ti spring and stainless steel round tubes. Tooth alignment was achieved efficiently and aesthetically without the conventional brackets.

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.179-195
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• 2009

Scince $^{201}$TI was introduced as a myocardial perfusion imaging agent in the early 1970s, scintigraphic evaluation of myocardial perfusion for the diagnosis of coronary artery disease is a valuable noninvasive diagnostic imaging modality. Stress radionuclide myocardial perfusion imaging is widely accepted to have high diagnostic and prognostic use in the assessment of patients with known or suspected coronary artery disease. With wise use of this nonivasive imaging technique, more patients are referred for stress perfusion imaging. Until now various protocols for stress testing and myocardial imaging were developed and used in worldwide. This article presented various protocols of stress testing and myocardial imaging for clinical use.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2005년도 ISMP
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• pp.201-212
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• 2005

[ $Epoxy/BaTiO_3$ ] composite embedded capacitor films (ECFs) were newly designed fur high dielectric constant and low tolerance (less than ${\pm}15\%$) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of specially formulated epoxy resin and latent curing agent, and in terms of coating process, a comma roll coating method is used for uniform film thickness in large area. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ composite ECF is measured with MIM capacitor at 100 kHz using LCR meter. Dielectric constant of $BaTiO_3$ ECF is bigger than that of $SrTiO_3$ ECF, and it is due to difference of permittivity of $BaTiO_3\;and\;SrTiO_3$ particles. Dielectric constant of $BaTiO_3\;&\;SrTiO_3$ ECF in high frequency range $(0.5\~10GHz)$ is measured using cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. Dielectric constant is calculated by observing the frequencies of the resonant cavity modes. About both powders, calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of epoxy matrix. For $BaTiO_3$ ECF, there is the dielectric relaxation at $5\~9GHz$. It is due to changing of polarization mode of $BaTiO_3$ powder. In the case of $SrTiO_3$ ECF, there is no relaxation up to 10GHz. Alternative material for embedded capacitor fabrication is $epoxy/BaTiO_3$ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming capacitor partially in desired part. But the screen printing makes surface irregularity during mask peel-off, Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, dielectric layer with improved thickness uniformity is successfully demonstrated. Using $epoxy/BaTiO_3$ composite ECP, dielectric constant of 63 and specific capacitance of 5.1nF/cm2 were achieved.

• Investigative Magnetic Resonance Imaging
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• 제7권2호
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• pp.100-107
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• 2003

목적 : 급성심근경색을 진단하는데 있어 심장자기공명영상의 유용성을 알아보고, 생존심근을 평가하는데 있어 Tl-201 심근관류 SPECT와 비교하고자 하였다. 대상 및 방법 : 흉통 및 호흡곤란이 있는 환자 중 심장자기공명영상과 Tl-201 SPECT를 시행한 17명을 후향적으로 조사하였다. 심장자기공명영상에서는 T2강조영상에서 심벽의 고신호 강도 유무, 영화영상에서 심벽 운동, Gd-DTPA 조영 증강 후 좌심실 벽의 관류 결손 및 주입 15분 후의 지연조영증강 유무를 평가하였다. T1-201 SPECT에서는 아데노신 부하 영상과 휴식기 영상을 얻어 관류 결손 유무와 관류 결손시 가역성 여부를 평가하였다. 결과 심장자기공명영상과 T1-201 SPECT 모두 급성심근경색을 진단하는데 통계적으로 의미가 있었고, T2강조영상, T1-201 SPECT, 지연조영증강 및 심벽운동 순으로 연관성이 있는 것으로 나타났고, 관류 결손은 통계적 유의성이 없었다. 생존심근 평가에 있어서는 두 검사간 유의한 차이가 없었으며, T2강조영상과 관류영상에서 T1-201 SPECT와 높은 일치율, 지연조영증강 및 심벽운동은 낮은 일치율을 보였다. 결론 : 심장자기공명영상은 급성심근경색을 진단하는데 매우 유의한 진단율을 보였고, 생존 심근여부의 판단에 있어 SPECT와 높은 일치율을 보였다. 그러나 각 검사별 판독 기준과 방법에서 많은 연구가 필요할 것으로 생각된다.